Operating agricultural vehicles such as tractors and harvesters often requires highly repetitive operations. For example, when plowing or planting a field, an operator must make repeated passes across a field. Due to the repetitive nature of the work and irregularities in the terrain, gaps and overlaps in the rows of crops can occur. This can result in damaged crops, overplanting, or reduced yield per acre. As the size of agricultural vehicles and farming implements continues to increase, precisely controlling their motion becomes more important.
Guidance systems are increasingly used for controlling agricultural and environmental management equipment and operations such as road side spraying, road salting, and snow plowing where following a previously defined route is desirable. This allows more precise control of the vehicles than is typically realized than if the vehicle is steered by a human. Many agricultural vehicles rely upon furrow followers which mechanically detect whether the vehicle is moving parallel to a previously plowed plant furrow. However, these guidance systems are most effective in flat terrain and when detecting furrows plowed in a straight line. Additionally, many of these systems require factory installation and are too expensive or inconvenient to facilitate after market installation.
A component for controlling the steering mechanism of the vehicle is used to control the movement of the vehicle in a desired direction. Thus, the guidance system generates a steering command which is implemented by the component which controls the steering mechanism. Often, the controlling component is directly coupled with and manipulates hydraulic pumps which comprise the power steering system of the vehicle. Other controlling components manipulate the steering wheel of the vehicle.
Prior art guidance systems are problematic in that there typically is no provision made for logically disengaging the guidance system. Thus, if a vehicle operator attempts to manually steer the vehicle (e.g., to pass to the side of a rock) the guidance system will continue trying to steer the vehicle in the original direction. This can be unsafe for the operator and may result in damage to the vehicle, or injury to the operator. Because there is no logical disengagement for the guidance system, the user has to manually operate motor mount 500 to disengage it from the steering wheel.